Sprinkler base



FIG. 1 is a perspective view of a lawn sprinkler base showing our new design;

FIG. 2 is a top plan view thereof;

FIG. 3 is a side elevational view thereof;

FIG. 4 is a front elevational view thereof; and

FIG. 5 is a rear elevational view thereof. 

The ornamental design for a sprinkler base, as shown. 